2-formyl imidazole is a widely-described product, some of the acetals of which are known, such as, in particular 2-dimethoxymethyl imidazole (Gary A. KOOLPE et al., J. Med. Chem., 1991, 34, 1368-1376; T. S. MANOHARAN et al., J. Org. Chem., 1988 53, 1107-1110), which compounds are obtained by standard acetalization of the aldehyde group. As for 2-formyl imidazole, it can be obtained either by oxidation of 2-hydroxymethyl imidazole, or by formylation of imidazole whose NH function is transitorily substituted by a protector group, or finally by hydrolysis of one of its aminal derivatives U.S. Pat. No. 3,812,189; K. L. KIRK, J. Org. Chem., 1978, 43, 4381-4383; L. A. M. BASTIAANSEN et al., J. Org. Chem., 1986, 51, 1891-1894). 2-formyl imidazole and its acetals are raw materials useful for obtaining various products which have valuable therapeutic or plant-protective properties. It is therefore beneficial to be able to have available a process which allows 2-formyl imidazole or one of its acetals to be obtained rapidly and economically in a single stage starting from inexpensive raw materials. With this aim in mind, the Applicant was surprised to discover a simple and rapid process allowing the preparation, in a single stage, of 2-formyl imidazole acetals.